Melt-out metal parts of complex shapes are made for use as cores in subsequently molded plastic components. Such cores are made of a low melting temperature alloy and are removed from the plastics components by melting the core and leaving the components. In another embodiment, metal alloys with low melting temperatures are used for encapsulating components such as turbine blades so they may be held for machining and other finishing steps. After use, the metal from the cores or encapsulations is re-melted and re-used. One example of an apparatus for casting metal alloys with low melting temperatures is disclosed in U.S. Pat. No. 4,676,296.